Transformer for electric-arc-welding apparatus



March 1 1927.

F. C. OWEN TRANSFORMER FOR susc'mc' ARC wswme APPARATUS Filed July 25, 1924 IIIIIII'! Patented Mar. 1, 1927.

FREDERICK O. OWEN, OF FAYETTEVILLE, NORTH C AROLHTA.

TRANSFORMER FOR ELECTRIG-ARC-WELDDN'G APPARATUS.

Application filed July 26,

This invention relates to transformers, and more particularly to transformers especially designed for use in connection with electric arc welding apparatus.

The invention has for one of its objects to improve and simplify the general construction of transformers of the character stated and to provide one which shall be so wound as to obviate the necessityof the use of any of the damping devices with which electric arc welding transformers are now equipped.

With the above and other objects in View,

the invention consists in the construction, combination and arrangement of parts hereinafter fully described and claimed, and illustrated in the accompanying drawings, wherein:

Figure 1 is an elevational view of a trans- Figure 3 is a sectional view taken on the plane indicated by the line 3-3 of Figure 1, and

Figure 4 is a sectional-view taken on the.

plane indicated by the line 4-4- of Figure 1. The transformer comprises as shown in the drawing, a laminated core 1 which is preferably of rectangular formation and provides a closed magnetic path. The primary winding of the transformer includes three coils, designated 2, 3 and 4, respectively. The coils 2,3 and 4 are arranged upon three adjacent legs of the core 1. The coils 2, 3 and 4 are in series, and the coils 2 and 4 are connected to a switch 5 by leads 6 and 7. Leads 8 and 9 extending from anysuitable source ofcurrent supply are also connected to the switch 5.

The secondary winding of the transformor includes a coil 10 which is mounted upon the coil 3 of the primary winding, and a coil 11 which is mounted upon the fourth leg of the'core 1. The coils 10 and 11 are preferably reversely wound, and the coil ll'is connected to the coil 10 and this coil is provided with a plurality of taps 12 to any one of which the electrode of the arc welding apparatus may be connected. The tap 12 to which the electrode is to be connected depends upon the amperage re- 1924. Serial No. 728,447.

quired to perform the welding operation.

The coil 10 is adapted to be connected to thetable of the apparatus by means of a lead 13.

Current flowing through the coils 2, 3 and 4, constituting the primary winding, tends to cause a magnetic flux to circulate .through the four legs of the core 1. Practically all thellux developed by this winding will thread the main secondary winding section or coil 10, because of the close association of this secondary coil with the primary winding, and flux in this part of the core remains substantially constant at all loads. As a result, the voltage generated in this secondary coil 10 likewise remains practically the .same at all times, and does not vary with the load.

The auxiliary section or coil 11 of the secondary winding, however, tends tov set up a flux independent of and opposed to that generated by the primary winding. Owing to the location of the coils, this secondary flux is confined substantially to that leg of the core on which the auxiliary coil 11 is mounted, while the primary flux alone threads the other three legs. 'The opposing fluxes meet in the neighborhood of the ends of that leg of the core on which the auxil-- iary coil 11 is mounted, and, as a result, a

substantial amount of flux is forced out of the closed metallic core into the air, or, in other words, a very noticeable flux leakage takes place at these points. The larger the current drawn from'the secondary winding, the greater this leakage becomes.

As a result of such leakage, the heavy secondary flux causes the coil 11 to develop high inductance, and act as an impedance coil, so that the phase of the voltage in this part of the secondary winding is shifted. It

' will thus be understood that when current flows through the primary winding, a constant main voltage and a variable secondary voltage is induced in the secondary winding. The reaction between'these voltages is such that there is induced in the secondary circuit alight current at light load and a heavy current at heavy load, with the result that a stable arc of high power factor may be read'-.

ily maintained during overhead, vertical and horizontal cutting welding or repairing of steel, wrought iron, cast iron, malleable iron, aluminum, brass, bronze, copper iliary secondary coil '11 with a series of taps I for different amperages, obviates the necessity of the use of-a damping device, or any themethod of the operation of the trans-' gether with the device which external resistance or mechanically operated current controller in connection with this transformer. It has been found that excellent results are attained when the core 1 is square. It isv to be understood, however, that I do not wish to be limited to the use of" the square core. The primary coils 2, 3 and 4 each preferably has the same number of turns or convolutions, and the secondary coil 11 preferably has agreater number of turns or convolutionsthan the secondary coil 10. Transformers embodying the invention are to be built to operate on either single or three phase alternating current, and are to be enclosed in wood, cast iron, steel or aluminum cases and are to be oil insulated and cooled, or air cooled.

From the foregoing description, takenin connection with the accompanying drawing, the advantages of the construction and former will be readily ap arent to those skilled in the art to which t e invention ap pertains, and whileI have described the principle of operation of the invention, to-

I now consider to be the best embodiment thereof, I desire to have it understood that the device shown is merely i11ustrat1ve ,.and that such changes may be made when desired as are within the scope of the invention as claimed.

What is claimed is 2- 1. A transformer comprising a core. providing a closed magnetic path, a primary coil on a. part of the core and adapted to cause substantially all the primary flux to traverse the other part of the core, dary coil on said other part of the core, and a second secondary coil connected to the first and arranged on that part of the 'core on which the primary coil is mounted.

2. A transformer comprising a core providing a closed magnetic path, a primary coil distributed about the major portion of the core, a secondar coil on the minor portion of the core, an a second secondary coil connected to the first secondary coil and arranged on the major portion of the core.

3. A transformer having a core consisting of a closed magnetic frame a rimary winding on said frame and distrlbuted around the same for a distance greater than one half the perimeter thereof, and a secondary winding comprising two sections, one section being interlinked with a portion of the primary winding, and the other section being wound onthat portion of the core between the ends-of said primary winding.

4. A transformer having a core consisting.

solely of aclosed rectangular frame, providing but 'a single primary winding distributed around three adjacent legs of said frame, and a secondary winding comprising two sections, one seemetallic magnetic path, a

tion being wound on the middle one of said three legs, and the other section being wound on the opposite or fourth leg of the frame. In testimony whereof I afiix my signature FREDERICK C. OWEN. 

